You are currently viewing our podiatry forum as a guest which gives you limited access to view all podiatry discussions and access our other features. By joining our free global community of Podiatrists and other interested foot health care professionals you will have access to post podiatry topics (answer and ask questions), communicate privately with other members, upload content, view attachments, receive a weekly email update of new discussions, access other special features. Registered users do not get displayed the advertisements in posted messages. Registration is fast, simple and absolutely free so please, join our global Podiatry community today!

Although in recent years the relationship between cognition and gait in Parkinson's disease (PD) has received increasing attention, the specific connections between gait patterns and cognitive features are not fully understood. The objective of this study was to describe the gait patterns in patients affected by PD with or without mild cognitive impairment (MCI+ and MCI−, respectively). We also sought to find an association between gait patterns and specific cognitive profiles. Using a gait analysis system, we compared the gait patterns among MCI+ patients (n = 19), MCI− patients (n − 24), and age- and sex-matched healthy subjects (HS; n = 20) under the following conditions: (1) normal gait, (2) motor dual task, and (3) cognitive dual task. In PD patients, gait parameters were evaluated in both the off and on states. Memory, executive, and visuospatial domains were assessed using an extensive neuropsychological battery. Compared with MCI− PD and HS, MCI+ PD patients displayed reduced step length and swing time and impairment of measures of dynamic stability; these dysfunctions were only partially reversed by levodopa. We also found that dual-task conditions affected several walking parameters in MCI+ PD in the off and on states relative to MCI− PD and HS. Factor analysis revealed 2 independent factors, namely, pace and stability. The latter was strongly and directly correlated to the visuospatial domain. In conclusion, dysfunctions on specific gait parameters, which were poorly responsive to levodopa and highly sensitive to dual-task conditions, were associated with MCI in PD patients. Importantly, visuospatial impairment was strongly associated with the development of instability and more generally with the progression of PD.

Objective
To compare the relative efficacy of visual versus auditory cueing on gait among individuals with Parkinson’s disease (PD).

Data Sources
A systematic search was completed up to September, 2011, using the following databases: EMBASE, Scopus, Medline, CINAHL, and PubMed.

Study Selection
Four authors searched the databases using the terms; Parkinson’s disease (including abbreviations), gait, cadence, step, pace, cueing, cues and prompt. All studies that evaluated the effect of cueing on gait in PD were selected by consensus of two pairs of authors who reviewed the titles and abstracts. Each pair of authors then applied the inclusion and exclusion criteria to each study and 25 articles were chosen. Inclusion criteria were cueing studies that reported pre and post outcome measures of gait parameters. Exclusion criteria were lack of data and studies that evaluated gait aids.
Data Extraction

Gait measures of cadence, stride length, and velocity, before and after cueing, were collected from each study. If data were represented in graphs, a pair of authors extracted the data points individually, then compared and averaged values.

Conclusions
The findings suggest that auditory cueing is more effective for treating gait disorders in PD. Further research is needed to determine the optimum auditory cueing strategy for gait improvements.

Gait and balance disturbances in Parkinson's disease (PD) can be debilitating and may lead to increased fall risk. Deep brain stimulation (DBS) is a treatment option once therapeutic benefits from medication are limited due to motor fluctuations and dyskinesia. Optimizing DBS parameters for gait and balance can be significantly more challenging than for other PD motor symptoms. Furthermore, inter-rater reliability of the standard clinical PD assessment scale, Unified Parkinson's Disease Rating Scale (UPDRS), may introduce bias and washout important features of gait and balance that may respond differently to PD therapies. Study objectives were to evaluate clinician UPDRS gait and balance scoring inter-rater reliability, UPDRS sensitivity to different aspects of gait and balance, and how kinematic features extracted from motion sensor data respond to stimulation. Forty-two subjects diagnosed with PD were recruited with varying degrees of gait and balance impairment. All subjects had been prescribed dopaminergic medication, and 20 subjects had previously undergone DBS surgery. Subjects performed seven items of the gait and balance subset of the UPDRS while wearing motion sensors on the sternum and each heel and thigh. Inter-rater reliability varied by UPDRS item. Correlation coefficients between at least one kinematic feature and corresponding UPDRS scores were greater than 0.75 for six of the seven items. Kinematic features improved (p<0.05) from DBS-OFF to DBS-ON for three UPDRS items. Despite achieving high correlations with the UPDRS, evaluating individual kinematic features may help address inter-rater reliability issues and rater bias associated with focusing on different aspects of a motor task.

Background
Gait impairments are well documented in those with PD. Prior studies suggest that gait impairments may be worse and ongoing in those with PD who demonstrate FOG compared to those with PD who do not.

Purpose
Our aim was to determine the effects of manipulating step length and cadence individually, and together, on gait coordination in those with PD who experience FOG, those with PD who do not experience FOG, healthy older adults, and healthy young adults.

Methods
Eleven participants with PD and FOG, 16 with PD and no FOG, 18 healthy older, and 19 healthy young adults walked across a GAITRite walkway under four conditions: Natural, Fast (+50% of preferred cadence), Small (−50% of preferred step length), and SmallFast (+50% cadence and −50% step length). Coordination (i.e. phase coordination index) was measured for each participant during each condition and analyzed using mixed model repeated measure ANOVAs.

Results
FOG was not elicited. Decreasing step length alone or decreasing step length and increasing cadence together affected coordination. Small steps combined with fast cadence resulted in poorer coordination in both groups with PD compared to healthy young adults and in those with PD and FOG compared to healthy older adults.

Conclusions
Coordination deficits can be identified in those with PD by having them walk with small steps combined with fast cadence. Short steps produced at high rate elicit worse coordination than short steps or fast steps alone.

Click to expand...

Highlights
► Small, fast steps are known to precede freezing of gait in Parkinson disease (PD).
► We asked how step length and/or cadence manipulation impacts gait coordination.
► We compared four groups: PD with and without freezing, and old and young controls.
► Taking small or small, fast steps worsened coordination in PD, particularly those with freezing.
► Taking small, fast or small and fast steps did not elicit any freezing episodes.

Background
Gait impairment in Parkinson's disease (PD) patients is characterized by the inability to generate appropriate stride length. Treadmill training has been proposed as a therapeutic tool for PD patients. However, it remains unknown whether treadmill training effects are different from overground walking training. Thus, our goal was to explore the effects of two training programs, walking on a treadmill and walking overground, in PD patients.

Methods
22 PD patients were randomly assigned to a treadmill or overground training group. The training program consisted of 5 weeks (3 sessions/week). Before and after the program we evaluated gait kinematics during walking at preferred and maximal speed; Timed Up and Go (TUG); static posturography and knee extensors strength. Gait parameters were reevaluated in the treadmill training group one month after the cessation of the training.

Results
Preferred speed walking improved in both groups after the training program. The treadmill training program, but not the overground, led to an improvement in the stride length at the preferred and maximal walking speed in the PD patients. In addition, the treadmill training group showed improvement of the TUG and static posturography tests. The improvement in gait parameters was maintained one month after the cessation of the treadmill training.

Conclusions
This study provides evidence of a specific therapeutic effect of treadmill training on Parkinsonian gait and balance. Walking on a treadmill may be used as an easy, effective and accessible way to improve the stride length and balance in PD patients.

Gait initiation is a transitional task involving a voluntary shift from a static, stable position to a relatively less-stable state of locomotion. During gait initiation, anticipatory postural adjustments precede stepping in order to generate forward momentum while balance is maintained. While deficits in gait initiation are frequently reported for persons with Parkinson's disease, there is a paucity of information regarding gait initiation performance in persons with Essential Tremor. We investigated anticipatory postural adjustments and spatiotemporal characteristics of gait initiation in persons with Essential Tremor and compared them to persons with Parkinson's disease as well as age-matched neurologically healthy adults. Twenty-four persons with Essential Tremor, 31 persons with Parkinson's disease, and 38 age-matched controls participated. We compared anterior–posterior and mediolateral center of pressure movements and spatiotemporal stepping characteristics during gait initiation among the three groups using Mann–Whitney U-tests with Bonferroni corrections for multiple comparisons and one-way ANOVAs. Persons with Parkinson's disease demonstrated significantly reduced displacement and velocity of the center of pressure during early phases of anticipatory postural adjustments relative to controls. Displacement of the center of pressure was also reduced in persons with Essential Tremor, although at a later stage of the gait initiation process. Persons with Parkinson's disease and Essential Tremor demonstrated similar reductions in step length during gait initiation when compared to controls. Persons with Parkinson's disease and Essential Tremor exhibit different deficits in gait initiation when compared to healthy older adults. Therefore, this study provides further evidence differentiating motor control features in these movement disorders.

Postural instability appears to be a dopamine resistance motor deficit in persons with Parkinson disease (PD); however, little is known about the effects of dopamine replacement on the relative biomechanical contributions of individual lower extremity joints during postural control tasks. To gain insight, we examined persons with PD using both clinical and laboratory measures. For a clinical measure of motor severity we utilized the Unified Parkinson Disease Rating Scale motor subsection during both OFF and ON medication conditions. For the laboratory measure we utilized data gathered during a rapid lower extremity force production task. Kinematic and kinetic variables at the hip, knee, and ankle were gathered during a counter movement jump during both OFF and ON medication conditions. Sixteen persons with PD with a median Hoehn and Yahr severity of 2.5 completed the study. Medication resulted in significant improvements of angular displacement for the hip, knee, and ankle. Furthermore, significant improvements were revealed only at the hip for peak net moments and average angular velocity compared to the OFF medication condition. These results suggest that dopamine replacement medication result in decreased clinical motor disease severity and have a greater influence on kinetics and kinematics proximally. This proximally focused improvement may be due to active recruitment of muscle force and reductions in passive restraint during lower extremity rapid force production.

Click to expand...

Highlights
•We investigated a rapid lower extremity force production task in persons with PD.
•Testing performed during both OFF and ON medication conditions.
•Significantly decreased motoric severity.
•Significantly increased angular displacement for the hip, knee, and ankle.
•Significantly increased moments and average angular velocity at the hip only.

Purpose: Recent studies suggest that walking on a treadmill improves gait, mobility, and quality of life of patients with Parkinson's disease (PD). Still, there is a need for larger-scale randomized controlled studies that demonstrate the advantages of treadmill training (TT) with control groups that receive similar amounts of attention. Moreover, to date, no study has combined speed and incline as parameters of progression. The aim of the study was to evaluate the effects of 24 weeks of TT, with and without the use of incline, on gait, mobility and quality of life in patients with PD.

Methods: The sample comprised 34 patients with PD, at Hoehn-Yahr stage 1.5 or 2. Participants were randomized to Speed TT, Mixed TT, and Control groups. The intervention consisted of 72 one-hour exercise sessions over 24 weeks. The main outcome measures are the MDS-UPDRS, the 39-item PD questionnaire, spatiotemporal parameters of gait and 6-minute walking distance. The measures were taken at baseline, mid-term and after 6 months.

Results: Both TT groups improved in terms of speed, cadence, and stride length during self-selected walking conditions at the study endpoint. Both groups also showed improvements in distance traveled. Only the Mixed TT group improved their quality of life. The Control group showed no progress.

Conclusions: Participants in this study showed significant improvements in walking speed and walking endurance following six months of TT. Improvements were observed after three months of intensive TT and persisted at six months. It appears that individuals with poorer baseline performance may benefit most from TT.

To date, little attempt has been made to compare or evaluate the effects of different physical exercise programs on gait disorders in people with Parkinson's disease (PD). This pilot study is aimed at obtaining preliminary data of the effects of two different exercise programs on gait parameters in people with PD by means of a biomechanical three-dimensional motion analysis. Twenty-five individuals with idiopathic PD participated either in a land-based (LB) or in a LB plus water-based (LWB) exercise program for 16 weeks. The efficacy of both exercise programs was quantified by means of a biomechanical gait analysis from which spatiotemporal and sagittal plane kinetic (gait speed, stride length, cadence, stride time, simple support time, double support time) and kinematic (angles of the hip, knee, and ankle joints) variables were recorded. Once the intervention ended, significant changes were observed in stride length and single/double support time variables in all the patients. The intergroup analysis revealed the existence of significant differences only in the gait Speed and hip Angle parameters. Few significant improvements in the amplitude of lower limb joints were found. These results suggest that land-based and land-plus-water-based exercise programs can be considered as a useful physical rehabilitation alternative, both equally capable of improving gait impairment on Parkinson's disease.

Click to expand...

Highlights
•Land and water plus land based exercises have similar effects on gait parameters.
•Both exercise programs improved stride length and single/double support time.
•Biomechanical analysis is not essential for testing the exercise effect on the gait.

Parkinson's disease (PD) impairs the ability to shape postural responses to contextual factors. It is unknown whether such inflexibility pertains to compensatory steps to overcome balance perturbations. Participants were instructed to recover balance in response to a platform translation. A step was necessary to recover balance when the translation was large, whereas a feet-in-place (FiP) response was sufficient when the translation was small (i.e. no step). We compared step trials that required a switch away from the current postural set (switch trials: step trials that were preceded by FiP trials) with non-switch trials (i.e. step trials were preceded by identical step trials). 51 PD patients (59±7 years) were compared with 22 healthy controls (60±6 years). In a second analysis, we compared a subgroup of 14 freezers (PD-FOG) with a subgroup of 14 non-freezers (PD-noFOG; matched for age, gender and disease severity). Compared to non-switch trials, switch trials resulted in poorer step execution and more steps needed to recover balance. These switching effects were similar in PD patients and controls, and in PD-FOG and PD-noFOG patients. Overall, PD patients demonstrated poorer stepping performance than controls. PD-FOG had a worse performance than PD-noFOG. Moreover, PD patients, and particularly PD-FOG patients, were less able to improve step performance with repetitive step trials, in contrast to controls. Thus, there was no PD-related deficit to switch to an alternative response strategy, neither in patients with FOG nor in patients without FOG. Difficulty to adapt the step trial-by-trial might have contributed to the absence of switch deficits in PD.

Click to expand...

Highlights
•Postural inflexibility is thought to affect balance maintenance in PD.
•We investigated whether postural inflexibility affects compensatory stepping.
•We compared a series of step responses to steps preceded by feet-in-place responses.
•Switch from a feet-in-place to step strategy led to deteriorated step performance.
•This switch effect was not different between PD patients and controls.

Objective: The differential diagnosis between atypical parkinsonism and Parkinson's disease is difficult, especially in the early stage. Severe postural instability, falls, and complex gait impairments are usually confined to the later stage of Parkinson's disease, while atypical parkinsonism patients may present a severe postural instability with consequent falls in the earlier stages.

Methods: We retrospectively studied 20 subjects with parkinsonism using clinical and baropodometric tools to give quantitative and objective data on the postural, balance, and gait disturbances.

Results: The statistical analysis between atypical parkinsonism and Parkinson's disease patients showed a significant difference in the frequency of long lead time parameter, foot area, foot load and speed, and, in particular, atypical parkinsonism patients presented a prevalent long lead time impairment (8/8 patients) when compared with Parkinson's disease patients.

Discussion: Beside significant differences in the clinical features between the Parkinson's disease and atypical parkinsonism, our study showed that baropodometric investigation may a valuable tool for the definition of postural and motor extrapyramidal abnormalities, permitting an earlier differentiation between atypical parkinsonism and Parkinson's disease.

Besides the continuous motor impairments that characterize Parkinson's disease (PD), patients are frequently troubled by sudden paroxysmal arrests or brief episodes of movement breakdown, referred to as 'freezing'. Freezing of gait (FOG) is common in advanced PD and typically occurs in walking conditions that challenge dynamic motor-cognitive control. Mounting evidence suggests that episodic motor phenomena during repetitive upper limb (e.g. writing), lower limb (e.g. foot tapping) and speech sequences resemble FOG and may share some underlying neural mechanisms. However, the precise association between gait and non-gait freezing phenomena remains controversial. This review aimed to clarify this association based on literature on non-gait freezing published between 2000 and 2013. We focused on clinical and epidemiological features of the episodes and their relevance to current influential models of FOG, including recent neuroimaging studies that used a non-gait freezing paradigm as a proxy for FOG. Although not capturing the full complexity of FOG, the neurobehavioral insights obtained with non-gait freezing paradigms will contribute to an increased understanding of disturbed brain-behavior output in PD.

Dynamics of postural control in Parkinson patients with and without symptoms of freezing of gait
Olena Pelykh, Anke-Maria Klein, Kai Bötzel, Zuzana Kosutzka, Josef IlmbergerGait & Posture; Articles in Press

Highlights
•We used linear and dynamical measures of postural sway in patients with Parkinson disease with and without freezing of gait.
•Radius was higher and sample entropy was lower in freezers as compared to healthy subjects.
•Dual-tasking increased sway path length in freezers, while normalized sway path did not change.
•The combination of static and dynamical measures adds valuable diagnostic information.

Click to expand...

Background
It has been suggested that dynamical measures such as sample entropy may be more appropriate than conventional measures when analyzing time series data such as postural sway. We evaluated conventional and dynamical measures of postural sway in Parkinson Disease (PD) patients with and without freezing episodes.

Methods
COP (center of pressure) data were recorded during quiet standing with eyes open, eyes closed and while performing a dual task. Data for 16 patients with freezing of gait, 17 patients with no history of freezing and 24 healthy subjects were analysed. The amount of postural sway was quantified using conventional measures, whereas for the characterization of the temporal structure of the COP data the normalized sway path and sample entropy was calculated.

Results
Mean radius was higher and sample entropy was lower in patients with freezing symptoms as compared to healthy subjects in all three conditions. Dual-tasking significantly increased sway path length in patients with freezing, while normalized sway path did not change over conditions in this group.

Conclusions
Our findings show that postural sway is characterized by a combination of large radius, short normalized sway path and high regularity of the COP only in patients with freezing. This pattern becomes most prominent in a dual-task paradigm. This may explain higher occurrence of gait freezing in dual task situations with subsequent higher risk of falls. Results suggested that dynamic measures may add valuable information for characterizing postural stability in PD patients.

Reports outlining the association between gait and cognition in Parkinson’s disease (PD) are limited because of methodological issues and a bias toward studying advanced disease. This study examines the association between gait and cognition in 121 early PD who were characterized according to motor phenotype, and 184 healthy older adults. Quantitative gait was captured using a 7 m GAITrite walkway while walking for 2 min under single-task conditions and described by five domains (pace, rhythm, variability, asymmetry, and postural control). Cognitive outcomes were summarized by six domains (attention, working memory, visual memory, executive function, visuospatial function, and global cognition). Partial correlations and multivariate linear regression were used to determine independent associations for all participants and for PD tremor-dominant (TD) and postural instability and gait disorder (PIGD) phenotypes, controlling for age, sex, and premorbid intelligence using the national adult reading test. Cognitive and gait outcomes were significantly worse for PD. Gait, but not cognitive outcomes, was selectively worse for the PIGD phenotype compared with TD. Significant associations emerged for two gait domains for controls (pace and postural control) and four gait domains for PD (pace, rhythm, variability, and postural control). The strongest correlation was for pace and attention for PD and controls. Associations were not significant for participants with the TD phenotype. In early PD, the cognitive correlates of gait are predominantly with fronto-executive functions, and are characterized by the PIGD PD phenotype. These associations provide a basis for understanding the complex role of cognition in parkinsonian gait.

Researchers at Newcastle University have found a definitive link between gait - the way someone walks - and early changes in cognitive function in people with Parkinson's disease.
And the findings, published today in the journal Frontiers in Aging Neuroscience could mean that gait may be used as an early warning sign to help predict the development of cognitive impairment and dementia in Parkinson’s. It has been known for several years that there is a link between gait disturbance and dementia in older adults, but until now the relationship has not been clear in Parkinson’s.

The Newcastle findings indicate that subtle changes in walking patterns – some of which are undetectable to the eye - could be an early warning sign of cognitive decline and could be a guide to alert medical practitioners that treatment is needed. Although there is no cure, early treatment can help manage symptoms.

Parkinson's disease

Over 120 people with Parkinson’s disease were tested making this the biggest study to date in early Parkinson’s Disease and they were compared to over 180 older adults. Volunteers were asked to walk for two minutes in the lab and their stride pattern was then analysed. Factors such as the length of stride, and sideways sway were looked at in a specially designed gait laboratory at the Clinical Ageing Research Unit, a clinical research facility jointly managed by Newcastle University and the Newcastle upon Tyne NHS Hospitals Foundation Trust.

Lynn Rochester, Professor of Human Movement Science at Newcastle University and lead author of the paper, said: “The relationship between gait and cognition has never been established this early on and in such a large group of Parkinson’s before. In the future walking patterns may be a useful early warning system to help identify dementia risk in Parkinson’s.

“Subtle changes in someone’s walking pattern, for example slowing down of steps, and increased sway from side to side are related to cognitive function even before changes are seen in cognitive tests.

“Ongoing work will confirm if it is possible to predict future cognitive decline and dementia risk. However this early work shows great promise.

“If we can use this and test people who may at risk, then we could pick up the early signs and begin treatment and advice.”

Motor impairment in Parkinson's disease (PD) is partly due to defective central processing of lower limb afferents. Concomitant alterations in cardiovascular autonomic control leading to orthostatic hypotension may worsen motor ability. We evaluated whether mechanical activation of feet sensory afferents could improve gait and modify the response of cardiovascular autonomic control to stressors in 16 patients (age 66 ± 2 yr) with idiopathic PD (Hoehn & Yhar scale 2-3) on their usual therapy. Eight subjects (group A) were randomized to undergo skin pressure (0.58 ± 0.04 kg/mm(2)) stimulation at the hallux tip and first metatarsal joint (effective stimulation; ES) of both feet. Eight remaining patients (group B) underwent sham stimulation (SS) followed by ES. Three-dimensional movement analysis provided quantitative indexes of movement disability before (baseline) and 24 h after ES and SS. Spectral analysis of heart rate and blood pressure variability provided markers of cardiac sympatho-vagal (LF/HF) and vascular sympathetic (LFSAP) modulations. Markers were measured at rest and during 75° head-up tilt, before and 24 h after ES and SS. After ES, step length and gait velocity increased, upright rotation velocity was enhanced, and step number was decreased. After ES, LFSAP declined. The increase in LF/HF and LFSAP induced by tilt was greater than before feet stimulation. No changes in gait and autonomic parameters were observed after SS. Twenty-four hours after ES, patients with PD showed improved gait and increased cardiac and vascular sympathetic modulation during upright position compared with baseline. Conversely, SS was ineffective on both movement and autonomic parameters, indicating a site specificity effect of the stimulation.

Impaired sensory processing in Parkinson's disease (PD) has been argued to contribute to balance deficits. Exercises aimed at improving sensory feedback and body awareness have the potential to ameliorate balance deficits in PD. Recently, PD SAFEx™, a sensory and attention focused rehabilitation program, has been shown to improve motor deficits in PD, although balance control has never been evaluated. The objective of this study was to measure the effects of PD SAFEx™ on balance control in PD. Twenty-one participants with mild to moderate idiopathic PD completed 12 weeks of PD SAFEx™ training (3 times/week) in a group setting. Prior to training, participants completed a pre-assessment evaluating balance in accordance with an objective, computerized test of balance (modified clinical test of sensory integration and balance (m-CTSIB) and postural stability testing (PST)) protocols. The m-CTSIB was our primary outcome measure, which allowed assessment of balance in both eyes open and closed conditions, thus enabling evaluation of specific sensory contributions to balance improvement. At post-test, a significant interaction between time of assessment and vision condition (p = 0.014) demonstrated that all participants significantly improved balance control, specifically when eyes were closed. Balance control did not change from pre to post with eyes open. These results provide evidence that PD SAFEx™ is effective at improving the ability to utilize proprioceptive information, resulting in improved balance control in the absence of vision. Enhancing the ability to utilize proprioception for individuals with PD is an important intermediary to improving balance deficits.

Conclusions: Posttraining improvements in speed, stride length, step length, double-stance, stance phase, and knee range of motion were observed in all groups, where no load (0%, 5%, or 10%) had any significant effect, suggesting that the influence of load did not make one experimental condition better than another. All participants benefitted from treadmill gait training, irrespective of the use of load.

A novel cognitive cueing approach to gait retraining in Parkinson’s disease:
A pilot study
Abstract
Background: Parkinson’s disease (PD) impairs gait performance, which can lead to falls and decreased
quality of life. This study examined the feasibility of implementing a novel home-based intervention designed
to elicit gait improvement in individuals with PD.
Methods: Five participants with PD completed a two-week home-based gait retraining intervention designed
around guided video feedback. Semi-structured interviews were conducted postintervention and two months
postintervention to acquire feedback from the participants about their experience with the intervention.
Spatiotemporal parameters of gait and functional mobility were assessed pre and postintervention and at two
months postintervention.
Results: Participants reported high levels of usability and expressed they believed that the intervention
improved their gait and led to a fortified sense of ability and revived sense of empowerment. Comparisons of
spatiotemporal and mobility parameters of gait identified that improvements occurred between
preintervention and postintervention—step length (x̄ = 10.7%), gait velocity (x̄ = 15.1%), and TUG scores (x̄
= 9.8%)—and between preintervention and two months postintervention—step length (x̄ = 3.9%), gait
velocity (x̄ = 9.9%), and TUG scores (x̄ = 4.2%).
Conclusions: Guided home-based video training has potential to be an effective treatment strategy for
improving gait impairment among individuals with PD.

Highlights
•Individuals with freezing of gait (FOG) have worse balance than those without FOG.
•Those with FOG have worse reactive postural responses and stability in gait.
•The Mini-BESTest, a time-efficient assessment of balance, is recommended in PD.

Click to expand...

Background
Freezing of gait (FOG) is a relatively common and remarkably disabling impairment associated with Parkinson disease (PD). Laboratory-based measures indicate that individuals with FOG (PD + FOG) have greater balance deficits than those without FOG (PD-FOG). Whether such differences also can be detected using clinical balance tests has not been investigated. We sought to determine if balance and specific aspects of balance, measured using Balance Evaluation Systems Test (BESTest), differs between PD + FOG and PD-FOG. Furthermore, we aimed to determine if time-efficient clinical balance measures (i.e. Mini-BESTest, Berg Balance Scale (BBS)) could detect balance differences between PD + FOG and PD-FOG.

Methods
Balance of 78 individuals with PD, grouped as either PD + FOG (n = 32) or PD-FOG (n =46), was measured using the BESTest, Mini-BESTest, and BBS. Between-groups comparisons were conducted for these measures and for the six sections of the BESTest using analysis of covariance. A PD composite score was used as a covariate.

Conclusions
The BESTest and Mini-BESTest, which specifically assessed reactive postural responses and stability in gait, were more likely than the BBS to detect differences in balance between PD + FOG and PD-FOG. Because it is more time efficient to administer, the Mini-BESTest may be the preferred tool for assessing balance deficits associated with FOG.

The objective of this paper is to analyse the gait of subjects with suffering
Parkinson's Disease (PD), plus to differentiate their gait from those of normal
people. The data is obtained from a medical gait database known as
Gaitpdb [1]. In the data set, there are 73 control subjects and 93 subjects
with PD. In our study, we first obtained the gait features using statistical
analysis, which include minimum, maximum, median, kurtosis, mean,
skewness, standard deviation and average absolute deviation of the gait
signal. Next, selection of the extracted features is performed using PSO
search, Tabu search and Ranker. Finally the selected features will undergo
classification using BFT, BPANN, k-NN, SVM with Ln kernel, SVM with Poly
kernel and SVM with Rbf kernel. From the experimental results, the
proposed model achieved average of 66.43%, 89.97%, 87.00%, 88.47%,
86.80% and 87.53% correct classification rates respectively.

Highlights
?We compared three types of cueing device and the immediate effects on gait initiation.
?We recorded 100 freezing and 91 non-freezing trials.
?Step length and Centre of Mass velocity showed clear measurable differences.
?Both the laser cane and the walking stick could benefit people with PD.

Click to expand...

Background
Freezing of gait (FOG) remains one of the most common debilitating aspects of Parkinson's disease and has been linked to injuries, falls and reduced quality of life. Although commercially available portable cueing devices exist claiming to assist with overcoming freezing; their immediate effectiveness in overcoming gait initiation failure currently unknown. This study investigated the effects of three different types of cueing device in people with Parkinson's disease who experience freezing.

Methods
Twenty participants with idiopathic Parkinson's disease who experienced freezing during gait but who were able to walk short distances indoors independently were recruited. At least three attempts at gait initiation were recorded using a ten camera Qualisys motion analysis system and four force platforms. Test conditions were: laser cane, sound metronome, vibrating metronome, walking stick and no intervention.

Results
During testing 12 of the 20 participants had freezing episodes, from these participants 100 freezing and 91 non-freezing trials were recorded. Clear differences in the movement patterns were seen between freezing and non-freezing episodes. The laser cane was most effective cueing device at improving the forwards/backwards and side to side movement and had the least number of freezing episodes. The walking stick also showed significant improvements compared to the other conditions. The vibration metronome appeared to disrupt movement compared to the sound metronome at the same beat frequency.

Conclusion
This study identified differences in the movement patterns between freezing episodes and non-freezing episodes, and identified immediate improvements during gait initiation when using the laser cane over the other interventions.

Highlights
?Postural coordination was objectively assessed in Parkinson's disease subjects.
?Use of hip strategy increased in PD when ON compared to OFF medication.
?Sway amplitude increased with medication and disease severity.
?Self-perception of balance was associated with objective measure of balance.

Click to expand...

Gait and Posture; In press

Altered postural control and balance are major disabling issues of Parkinson's disease (PD). Static and dynamic posturography have provided insight into PD's postural deficits; however, little is known about impairments in postural coordination. We hypothesized that subjects with PD would show more ankle strategy during quiet stance than healthy control subjects, who would include some hip strategy, and this stiffer postural strategy would increase with disease progression.

We quantified postural strategy and sway dispersion with inertial sensors (one placed on the shank and one on the posterior trunk at L5 level) while subjects were standing still with their eyes open. A total of 70 subjects with PD, including a mild group (H&Y≤2, N = 33) and a more severe group (H&Y≥3, N = 37), were assessed while OFF and while ON levodopa medication. We also included a healthy control group (N = 21).

Results showed an overall preference of ankle strategy in all groups while maintaining balance. Postural strategy was significantly lower ON compared to OFF medication (indicating more hip strategy), but no effect of disease stage was found. Instead, sway dispersion was significantly larger in ON compared to OFF medication, and significantly larger in the more severe PD group compared to the mild. In addition, increased hip strategy during stance was associated with poorer self-perception of balance.

The aim of the present study was to test the hypothesis that people with Parkinson's disease (PD) are more dependent than healthy individuals on visual information in an on-line manner to guarantee accurate foot placement into an intended stepping target. Patients with PD and age-matched healthy participants walked along a pathway and were required to step onto either one or two targets during the walk trial. Outcome measures included absolute error (accuracy) and error variability (precision) of foot placement onto the first target, and the time interval between the gaze transfer away from the first target and heel contact on the same target. When there was a single target in the travel path, both groups fixated the target until after heel contact on the target. However, when challenged with an additional target, both groups transferred their gaze from the first target prior to heel contact. Interestingly, only people with PD increased anterior-posterior absolute error (first target) when there was more than one target in the travel path. Premature gaze transfer was associated with decline in stepping accuracy (anterior-posterior absolute error) in people with PD. These findings suggest that both people with PD and healthy individuals prioritize the planning of future actions over the execution of ongoing steps, while walking. Additionally, current findings support the notion people with PD are more dependent on visual feedback to make on-line corrections and adjustments to their foot trajectory in order to guarantee accurate foot placement into an intended stepping target.

Highlights
Patients with PD and healthy individuals seek to improve balance and safety after fatigue.
The gait adjustments after muscle fatigue were less pronounced in patients with PD.
The physical activity level did not interact with lower limb muscle fatigue.

Click to expand...

Patients with Parkinson's disease (PD) are more susceptible to muscle fatigue, which can damage their gait. Physical activity can improve muscle condition, which is an important aspect during walking. The aim of this study was to analyze the effects of lower limb muscle fatigue on gait in patients with PD and healthy individuals, grouped according to physical activity level. Twenty Patients with PD (PD group) and 20 matched individuals (control group) were distributed according to physical activity level into four subgroups of ten individuals (active and inactive). Participants performed three walking trials before and after lower limb muscle fatigue, induced by a repeated sit-to-stand task on a chair. Kinematic (stride length, width, duration, velocity and percentage of time in double support) and kinetic (propulsive and breaking anterior-posterior and medio-lateral impulse) gait parameters were analyzed. In both groups, participants increased stride length and velocity and decreased stride duration and braking vertical impulse after lower limb muscle fatigue. The PD groups presented higher step width and percentage of double time support than the control groups before muscle fatigue. The control groups increased step width and decreased percentage of time in double support, while the PD groups did not change these parameters. For physical activity level, active individuals presented longer stride length, greater stride velocity, higher braking and propulsive anterior-posterior impulse and shorter step width than inactive individuals. Groups sought more balance and safety after lower limb muscle fatigue. Physical activity level does not appear to modify the effects of lower limb muscle fatigue during unobstructed walking in individuals with PD or controls.

Highlights
?Balance is the strongest predictor of gait and mobility impairment in PD.
?Balance confidence affects mobility outcomes, but to a smaller extent.
?Age is a better predictor for longer duration and more complex tasks.
?Executive function explains a small portion of variance during forward walking.

Click to expand...

Mobility and gait limitations are major issues for people with Parkinson disease (PD). Identification of factors that contribute to these impairments may inform treatment and intervention strategies. In this study we investigated factors that predict mobility and gait impairment in PD. Participants with mild to moderate PD and without dementia (n = 114) were tested in one session ?off? medication. Mobility measures included the 6-Minute Walk test and Timed-Up-and-Go. Gait velocity was collected in four conditions: forward preferred speed, forward dual task, forward fast as possible and backward walking. The predictors analyzed were age, gender, disease severity, balance, balance confidence, fall history, self-reported physical activity, and executive function. Multiple regression models were used to assess the relationships between predictors and outcomes. The predictors, in different combinations for each outcome measure, explained 55.7% to 66.9% of variability for mobility and 39.5% to 52.8% for gait velocity. Balance was the most relevant factor (explaining up to 54.1% of variance in mobility and up to 45.6% in gait velocity). Balance confidence contributed to a lesser extent (2.0% to 8.2% of variance) in all models. Age explained a small percentage of variance in mobility and gait velocity (up to 2.9%). Executive function explained 3.0% of variance during forward walking only. The strong predictive relationships between balance deficits and mobility and gait impairment suggest targeting balance deficits may be particularly important for improving mobility and gait in people with PD, regardless of an individual?s age, disease severity, fall history, or other demographic features.

Articles in Press
To read this article in full, please review your options for gaining access at the bottom of the page.A smartphone-based architecture to detect and quantify freezing of gait in Parkinson’s disease
Marianna Capeccic et alGait and Posture; Article in Press

Highlights
•A smartphone application for real-time detection of freezing of gait is presented.
•The application is tested on 20 patients with Parkinson’s disease and FOG.
•An innovative algorithm is compared to a traditional one.
•The architecture is highly reliable in FOG detection, even if it occurs at turning.

Click to expand...

Introduction
The freezing of gait (FOG) is a common and highly distressing motor symptom in patients with Parkinson’s Disease (PD). Effective management of FOG is difficult given its episodic nature, heterogeneous manifestation and limited responsiveness to drug treatment.

Methods
In order to verify the acceptance of a smartphone-based architecture and its reliability at detecting FOG in real-time, we studied 20 patients suffering from PD-related FOG. They were asked to perform video-recorded Timed Up and Go (TUG) test with and without dual-tasks while wearing the smartphone. Video and accelerometer recordings were synchronized in order to assess the reliability of the FOG detection system as compared to the judgement of the clinicians assessing the videos. The architecture uses two different algorithms, one applying the Freezing and Energy Index (Moore-B?chlin Algorithm), and the other adding information about step cadence, to algorithm 1.

Results
A total 98 FOG events were recognized by clinicians based on video recordings, while only 7 FOG events were missed by the application. Sensitivity and specificity were 70.1% and 84.1%, respectively, for the Moore-B?chlin Algorithm, rising to 87.57% and 94.97%, respectively, for algorithm 2 (McNemar value = 28.42; p = 0.0073).

Conclusion
Results confirm previous data on the reliability of Moore-B?chlin Algorithm, while indicating that the evolution of this architecture can identify FOG episodes with higher sensitivity and specificity. An acceptable, reliable and easy-to-implement FOG detection system can support a better quantification of the phenomenon and hence provide data useful to ascertain the efficacy of therapeutic approaches.

Previous studies have shown that gait patterns differ between Parkinson's disease (PD) patients and controls. However, almost all these studies focused only on univariate time series of a single variable. This approach cannot reveal detailed information of foot loading dynamics and the cooperative relationships of different anatomical plantar foot areas when the subjects walk. By contrast, we propose a novel multivariate method for analyzing gait patterns of the PD patients: Gait Influence Diagrams (GIDs). These are constructed by analyzing the Wiener-Akaike-Granger-Schweder influences between vertical ground reaction force signals at different plantar areas of both feet. In this paper, we use the particular case of WAGS influence measures known as "extended Granger causality analysis". GIDs are directed graphs, with arrows indicating those influences that are significantly different between PD patients and healthy subjects. We confirm prior clinical observations that Parkinsonian gait differs significantly from the healthy one in the anterior-posterior movement direction. A new finding is that there are also pathological changes in the lateral-medial direction. Importantly, gait asymmetry for the PD patients is clearly evident in GIDs, even in earlier stages of the disease. These results suggest that GID might be of use in future PD gait pattern studies.

Although hydrotherapy is one of the physical therapies adopted to optimize gait rehabilitation in people with Parkinson disease, the quantitative measurement of gait-related outcomes has not been provided yet. This work aims to document the gait improvements in a group of parkinsonians after a hydrotherapy program through 2D and 3D underwater and on land gait analysis. Thirty-four parkinsonians and twenty-two controls were enrolled, divided into two different cohorts. In the first one, 2 groups of patients underwent underwater or land based walking training; controls underwent underwater walking training. Hence pre-treatment 2D underwater and on land gait analysis were performed, together with post-treatment on land gait analysis. Considering that current literature documented a reduced movement amplitude in parkinsonians across all lower limb joints in all movement planes, 3D underwater and on land gait analysis were performed on a second cohort of subjects (10 parkinsonians and 10 controls) who underwent underwater gait training. Baseline land 2D and 3D gait analysis in parkinsonians showed shorter stride length and slower speed than controls, in agreement with previous findings. Comparison between underwater and on land gait analysis showed reduction in stride length, cadence and speed on both parkinsonians and controls. Although patients who underwent underwater treatment exhibited significant changes on spatiotemporal parameters and sagittal plane lower limb kinematics, 3D gait analysis documented a significant (p < 0.05) improvement in all movement planes. These data deserve attention for research directions promoting the optimal recovery and maintenance of walking ability.

Brain regions important for controlling movement are also responsible for rhythmic processing. In Parkinson disease (PD), defective internal timing within the brain has been linked to impaired beat discrimination, and may contribute to a loss of ability to maintain a steady gait rhythm. Less rhythmic gait is inherently less efficient, and this may lead to gait impairment including reduced speed, cadence, and stride length, as well as increased variability. While external rhythmic auditory stimulation (e.g. a metronome beat) is well-established as an effective tool to stabilize gait in PD, little is known about whether self-generated cues such as singing have the same beneficial effect on gait in PD. Thus, we compared gait patterns of 23 people with mild to moderate PD under five cued conditions: uncued, music only, singing only, singing with music, and a verbal dual-task condition. In our singlesession study, singing while walking did not significantly alter velocity, cadence, or stride length, indicating that it was not excessively demanding for people with PD. In addition, walking was less variable when singing than during other cued conditions. This was further supported by the comparison between singing trials and a verbal dual-task condition. In contrast to singing, the verbal dual-task negatively affected gait performance. These findings suggest that singing holds promise as an effective cueing technique that may be as good as or better than traditional cueing techniques for improving gait among people with PD.

Highlights
•GVI scores in Parkinson’s disease showed similar variability to healthy older adults.
•GVI scores showed low correlations to other functional performance measures.
•GVI scores could not distinguish mild from moderate disease severity.
•The GVI should not be used to quantify gait variability in individuals with Parkinson’s disease.

Click to expand...

Increased step-to-step variability is a feature of gait in individuals with Parkinson’s disease (PD) and is associated with increased disease severity and reductions in balance and mobility. The Gait Variability Index (GVI) quantifies gait variability in spatiotemporal variables where a score ≥ 100 indicates a similar level of gait variability as the control group, and lower scores denote increased gait variability. The study aim was to explore mean GVI score and investigate construct validity of the index for individuals with mild to moderate PD. 100 (57 males) subjects with idiopathic PD, Hoehn &Yahr 2 (n = 44) and 3, and ≥ 60 years were included. Data on disease severity, dynamic balance, mobility and spatiotemporal gait parameters at self-selected speed (GAITRite) was collected. The results showed a mean overall GVI: 97.5 (SD 11.7) and mean GVI for the most affected side: 94.5 (SD 10.6). The associations between the GVI and Mini- BESTest and TUG were low (r = 0.33 and 0.42) and the GVI could not distinguish between Hoehn &Yahr 2 and 3 (AUC = 0.529, SE = 0.058, p = 0.622). The mean GVI was similar to previously reported values for older adults, contrary to consistent reports of increased gait variability in PD compared to healthy peers. Therefore, the validity of the GVI could not be confirmed for individuals with mild to moderate PD in its current form due to low associations with validated tests for functional balance and mobility and poor discriminatory ability. Future work should aim to establish which spatiotemporal variables are most informative regarding gait variability in individuals with PD.

The aim of our study was to identify and quantify spatiotemporal and kinematic gait parameters obtained by 3D gait analysis (GA) in a group of Parkinson's disease (PD) patients compared with healthy subjects in order to investigate whether early PD patients could present an abnormal gait pattern. Forty-four patients affected by early-stage PD compared with a control group were analyzed. All participants were evaluated with 3D GA in the gait laboratory. The greatest significance in temporal parameters was found in cadence (102.46 ± 13.17 steps/min in parkinsonian patients vs 113.84 ± 4.30 steps/min in control subjects), followed by stride duration (1.19 ± 0.18 seconds right limb and 1.19 ± 0.19 seconds left limb in PD patients vs 0.426 ± 0.16 seconds right limb and 0.429 ± 0.23 seconds left limb in normal subjects) and stance duration. Marked differences were also found in the swing phase and in swing duration (p<0.05), while the stance phase was not significantly different in patients compared with healthy subjects. A statistically different velocity in PD patients (0.082 ± 0.29 m/s) vs healthy subjects (1.33 ± 0.06 m/s) was shown by spatial parameter analysis. Step width, stride length and swing velocity were highly significant parameters, as was average velocity. Our study highlighted some distinguishing characteristics of gait in early PD. Ambulation disorders may be present in the early stage of PD and their detection allows for early medical treatment and possible rehabilitation.

Clinical balance scales indicate worse postural control in people with Parkinson’s disease who exhibit freezing of gait compared to those who do not: a meta-analysis
Esther M.J. Bekkers et alGait and Posture; Article in Press

Highlights
•Postural control is more profoundly affected in FOG+ compared to FOG-.
•Clinical balance scales are sensitive to detect differences between PD subgroups.
•Medication does not influence balance differences between FOG+ and FOG-.

Click to expand...

Postural instability and freezing of gait (FOG) are key features of Parkinson’s disease (PD) that are closely related to falls. Uncovering the postural control differences between individuals with and without FOG contributes to our understanding of the relationship between these phenomena. The objective of this meta-analysis was to investigate whether postural control deficits, as detected by clinical balance scales, were more apparent in FOG+ compared to FOG-. Furthermore, we aimed to identify whether different scales were equally sensitive to postural control deficits and whether medication affected postural control differentially in each subgroup. Relevant articles were identified via five electronic databases. We performed a meta-analysis on nine studies which reported clinical balance scale scores in 249 freezers and 321 non-freezers. Methodological analysis showed that in 5/9 studies disease duration differed between subgroups. Despite this drawback, postural control was found to be significantly worse in FOG+ compared to FOG-. All included clinical balance scales were found to be sufficiently sensitive to detect the postural control differences. Levodopa did not differentially affect postural control (p = 0.21), as in both medication states FOG+ had worse postural stability than FOG-. However, this finding warrants a cautious interpretation given the limitations of the studies included. From subscore analysis, we found that reactive and dynamic postural control were the most affected postural control systems in FOG+. We conclude that our findings provide important evidence for pronounced postural instability in individuals with FOG, which can be easily picked up with clinical evaluation tools. Posturographic measures in well-matched subgroups are needed to highlight the exact nature of these deficits.

Objectives
To investigate differences in toe clearance between people with PD and age-matched healthy elderly (HE) during comfortable walking and to study the effects of dual-tasking and the use of an attentional strategy emphasizing heel strike on toe clearance.

Results
People with PD had less maximal toe clearance in the end of the swing phase and a smaller foot strike angle than HE during all three walking conditions. Impairments significantly diminished during heel strike focused walking improving performance to equal the HE. Heel strike focused walking resulted in an increased minimal toe clearance and a longer duration of end swing phase when compared to walking with and without a dual-task. The attentional strategy to focus on heel strike improved the stride length when compared to dual-task walking. Surprisingly, minimal toe clearance did not differ between PD and HE in any of the conditions and there were no dual-task effects on toe clearance.

Conclusion
These findings provide evidence favoring the potential incorporation of an attentional strategy focusing on the heel strike in PD gait rehabilitation.

Bradykinesia is a prominent problem for persons with Parkinson's disease (PD) and has been studied extensively with upper extremity tasks; however there is a lack of research examining bradykinesia in targeted lower extremity tasks related to mobility. Navigating steps and curbs are challenging tasks for older adults and neurologically impaired and thus utilizing these behaviors provides ecological validity to the study of bradykinesia. Herein we assess differences in step negotiation performance between individuals with PD and aged matched older adults. Three-dimensional kinematics and ground reaction forces were collected while 12 participants with PD and 12 older adults performed a single step up onto a platform. Persons with PD spent a significantly greater amount of time in the heel lift phase (P=0.0003, d=1.80). Peak vertical foot velocity of the lead foot was also significantly less in PD (P=0.02, d=1.05). Lastly, persons with PD displayed reduced sagittal hip and knee range of motion during the trail step (P=0.01, d=1.20 and P=0.02, d=1.05, respectively). Parkinson's participants exhibited slight decrement in step negotiation execution. Increased step time and decreased foot velocity and range of motion were attributes associated with Parkinson's step negotiation performance. Contrary to our hypothesis, in many comparisons, persons with PD during their best medicated state performed comparable to older adults, indicative of successful pharmacotherapy. Rehabilitation efforts can seek to improve performance in motor control tasks such as step negotiation, by restoring the relationship between perceived and actual motor output and enhancing muscle coordination and output as well as ranges of motion.

While Parkinson's disease (PD) is traditionally viewed as a motor disorder, there is mounting evidence that somatosensory function becomes affected as well. However, conflicting reports exist regarding whether plantar sensitivity is reduced in early-onset PD patients. Plantar sensitivity was assessed using monofilaments and a gold-standard, two-interval two-alternative forced choice vibrotactile detection task at both 30 and 250Hz. Lower-limb cutaneous reflexes were assessed by delivering continuous, sinusoidal vibration at 30 and 250Hz while recording muscle activity in Tibialis Anterior. We found no evidence of elevated plantar thresholds or dysfunctional lower-limb cutaneous reflexes in PD patients ON medication. We also found no acute effect of ceasing L-dopa intake on either plantar sensitivity or cutaneous reflexes. Our finding of intact cutaneous function in PD supports the further exploration of therapeutics that enhance plantar sensitivity to minimize postural instability, a source of considerable morbidity in this clinical population.

OBJECTIVES:
To investigate differences in toe clearance between people with PD and age-matched healthy elderly (HE) during comfortable walking and to study the effects of dual-tasking and the use of an attentional strategy emphasizing heel strike on toe clearance.
DESIGN:
Observational cross-sectional study.
SETTING:
Camera-based 3D gait laboratory.
PARTICIPANTS:
Ten persons with PD (Hoehn and Yahr I to III) having mild gait disturbances and 10 HE.
INTERVENTIONS:
Participants walked for two minutes under three conditions at comfortable pace: single-task walking, attending to heel strike during single-task walking, and dual-task walking.
MAIN OUTCOME MEASURES:
Minimal and maximal toe clearance; foot strike angle with the ground.
RESULTS:
People with PD had less maximal toe clearance in the end of the swing phase and a smaller foot strike angle than HE during all three walking conditions. Impairments significantly diminished during heel strike focused walking improving performance to equal the HE. Heel strike focused walking resulted in an increased minimal toe clearance and a longer duration of end swing phase when compared to walking with and without a dual-task. The attentional strategy to focus on heel strike improved the stride length when compared to dual-task walking. Surprisingly, minimal toe clearance did not differ between PD and HE in any of the conditions and there were no dual-task effects on toe clearance.
CONCLUSION:
These findings provide evidence favoring the potential incorporation of an attentional strategy focusing on the heel strike in PD gait rehabilitation.